Insulator for high-tension transmission-lines.



C. E. EVELETH.

INSULATOR FOR HIGH TENSION TRANSMISSION LINES.

APPLIOATIONIILEDSEPT&3.1908.

FlquL.

EHARLEEIEEVELETH AT T T Patented Apr. 6, 1909.

INVENTDRZ UNITED sTkTEs; PATENT oEFroE.

CHARLES E. EVELETH,. or scHEnEoTADY, YORK, Assienoaro GENERAL ELECTRIC COMPANY, a CORPORATION OF NEW .YORK.

IivsULA'ron non HIGH-TENSION; TRANSMISSION-LINES.

' Speeificationof Letters Patent.

Patented April 6, .1 909.

Application filed September 3, 1908. SeriaI No. 451,491.

To all whom it may concern:

Be it known'that IfCHAnLns E. EVEL TI-I, .a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful improvements in Insulators for High- Tension Transmission-Lines, of which the following-is a specification.

This invention relates to insulators for overhead conductors carrying electric currents of high potential, and it is especially intendedforu'se in electric railway installations which employ a catenary system of suspension for the working conductor. The ordinary glass or porcelain insulator ele vated on a pole or cross-arm is conspicuous by its size and color and seems to exert a great attraction upon would-be marksmen, who find a peculiar pleasure in throwing stones and other missiles at such insulators and in shooting at them with sling-shots, airns and-firearms of various sorts.

neck, so that it is liable to become loose and fall, and in anyevent the removal of all or a portion of the shell or petticoat close to the surface.

may remain intact.

neck reduces the leakage surface to a dangerous degree. Breakage of insulators, therefore, not only causes expense to the com pany operating the line, but it is a source of danger to individuals and apparatus, owing to the liability of short circuits and grounds, which are serious matters on lines carrying several thousand volts. I

The object of'my invention is to reduce as far as possible the danger from this wanton destruction of insulators, and laccomplish this result by so constructing the insulators that if they are struck by a stone, bullet or other missile they will give way only in-such parts as can be spared without diminishing their holding and supporting capacity, and without dangerously reducing their leakage In other words, I provide each insulator with one or more weakened lines, along which breakage may occur, and I so locate these lines as to limit the breakage to the outer portions of the insulator, so that its central portion which supports the wire I find by experiment that these breakage lines are most effective if they are located in the petticoat of the insulator and coincide more or less closely with chords of segments of said petticoat.

An 'insu ator generally breaks close to or at the In the accompanying drawing, Figure 1 is a perspective view of an insulator made in accordance with my invention; Fig. 2 is a top plan view of the same, and'FigFiB is a side elevation, partly in section.

The insulator shown comprises two parts, a central shell 1, and a combined head 2 and flaring petticoat 3-. The shell contains a socket 4, preferably provided with internal customary pin support.

The head 'or'cap is fastened by cement 6 screw-threads or grooves 5', to enable said' shell to be secured upon the upper end of theupon the upper end of the shell. Ithas a transverse groove 7 for the line wire, messengel cable or the like, and a circumferential groove 8 around its neck for the fastening wire or clamp.

The petticoat is provided with a 1 plurality of grooves 9, preferably in one sur ace only and that theupper surface, and preferably coinciding more or less /with the chords of segments of the peri hery of said etticoat. The segments thus efined by saic weake'n ing grooves preferably overlap at their ends, so that the chordalgrooves 9 intersect at their ends, as shown. The grooves are illustratedas being straight, but they are not necessarily so, as is evident. 1

I find by experiment that when a petticoat is struck by a missile, it tends to break on a straight line following more or less closely the chord of the segment which is broken out and generally running close to or across the neck. Hence, by arranging the weakening grooves in the manner shown, this natural tendency to break on chordal lines is taken advantage of to confine the lost ortion to a comparatively small area and ocate the break at a distance from the neck. The number of breakage lines is immaterial, but I prefer about half a dozen, as shown in Fig. 2. Y

. t will be seen that an insulator of this kind may have the outer ortion of its petticoat entirely removed without impairing the cap or the central shell, and therefore without releasing the wire or cable which it sup orts. Moreover, enough of the petticoat will be left to afford a fairly good leakage surface.

Inasmuch as it requires several distinct and separate blows to break off the entire rim portion of the petticoat, such an'event is not iable to occur before the injury is discovered by a lineman and the (lan'n'iged insulator replared. by a whole one.

The invention has been. illustrated. in iis applieation to an insulator having a separate inner shell. and a single. pettieoat portion, but it is evidently capable. of use with a great variety of ii'isulators involving a dillerent number of parts and other (mistruotions.

What I claim as new and desire to secure by Letters Patent of the United St ates, -is

1. An insulator having a pettieoat provided with weakening grooves.

2. An insulator having a pettieost vided with transverse grooves.

3. An insulator having a pettieoat vided with weakening grooves defining;- ments of its periphery.

4. An insulator having a etticoat propro- 5 (Agvi le l with breakage grooves located in ehords 01 segments of its periplie" n 5. An insulator liavlng a petticoat proviiled with wealn'ining grooves defining segpro- 1 limits of its periphery and i'ntcu'secting at. their ends.

6. .n insulator provided with a Petticoat having weakening grooves located along natural lines of breakage.

7. An insulator having its pettieoat Weakened at a point removed from its neck.

In witness whereof, I have hereunto set my hand this 2nd day of September, 1908.

CHARLES E. E'VELETl-I.

Witnesses:

BENJAMIN HULL, h'hmoixmn E. VVOQL'LEY. 

